Commonly owned U.S. Pat. Nos. 5,859,952 and 5,677,982 disclose humidifiers with anticontamination utilizing ultraviolet radiation or UV. The water is dispersed, after it has been subjected to antimicrobial inactivation by the ultraviolet radiation via an ultrasonic atomizer, heater or wettable surface or filter over which or through which air can be passed. In that system the UV antimicrobial action takes place in a chamber through which the water passes and which has at least one window transparent to the UV radiation so that the water in the chamber can be exposed to the UV.
While this system has proved to be effective in practice, it is frequently desirable to afford greater assurance of the effectiveness of the antimicrobial field, namely, the ultraviolet radiation.